Cystic floor-of-mouth mass

A thyroglossal cyst is a fibrous cyst that forms from a persistent thyroglossal duct. Thyroglossal cysts can be defined as an irregular neck mass or a lump which develops from cells and tissues left over after the formation of the thyroid gland during developmental stages.Thyroglossal cysts are the most common cause of midline neck masses and are generally located caudal to (below) the hyoid bone. [Source: Wikipedia ]